Cardiovascular disease (CVD) is the leading cause of death in the US, with total costs (including hypertension) of nearly $300 billion in 2008. The progression of CVD occurs over many years and is influenced by a series of demographic, clinical and psychosocial factors that vary across populations. In the US, these factors are least well understood among Asians and Pacific Islanders. Asians are now the fastest-growing minority population in the United States, increasing 43% from 10.2 million to 14.7 million in the past decade.7 Similarly, Native Hawaiian and other Pacific Islander populations have increased by more than 35% during this same time. While Asian populations in the U.S. are commonly thought to be healthier than other minority groups and non-Hispanic Whites, emerging research suggests that some Asian subgroups and Pacific Islanders might be at higher risk for CVD and associated poor outcomes. With such population growth, the health of these populations will have an increasing impact upon future US public health care needs and costs. This compelling CVD knowledge gap about API populations has prompted the American Heart Association and the National Lung, Heart and Blood Institute to call for research that will improve the understanding of CVD among API subpopulations.10 To fill this important gap in knowledge about health disparities among API, we will measure CVD prevalence and outcomes among 9 well-defined API populations, and comprehensively assess the role of demographic, clinical and psychosocial factors in explaining observed differences in CVD prevalence and outcomes among these groups. The multidisciplinary study team brings broad expertise in epidemiology, cardiovascular disease, and the role of social and psychological factors in health disparities. The study population will be drawn from the membership of two large, integrated health care systems located in different geographic regions with large clusters of Asian and Pacific Islander residents (Hawaii and northern California). The study will leverage the rich detail of more than a decade of clinical data contained within electronic health records (EHR) systems of both health plans. We will also collect patient reported data via a large-scale survey of 10,000 people. The study aims are to: 1. Describe differences in the prevalence of CVD among Asian, Pacific Islander, and mixed-race API subpopulations; 2. Determine whether demographic, clinical and psychosocial factors explain observed differences in CVD prevalence among these populations; and 3. Describe differences in CVD outcomes among these populations, including quality of life, and determine whether demographic, clinical and psychosocial factors explain observed differences. Study results will provide important new evidence about underlying factors associated with CVD prevalence and outcomes among rapidly growing, diverse populations in the U.S. This information will provide strategic guidance for targeted interventions at multiple levels-provider, patient, and health system-to reduce CVD mortality and morbidity.